As a trustee and beneficiary of a trust, if I get a loan and use the trust as collateral, what happens when the trust is executed?

A typical trust agreement would allow the Trustee to borrow money using trust assets as collateral. The specific trust agreement would have to be examined to ensure such authority is granted. The funds borrowed would have to be used for a trust purpose. The trustee has fiduciary responsibilities to the trust, including the duty of loyalty which includes avoidance of self-dealing.